#background_box{
    width: 250px;
    height: 250px;
    border:1px solid black;
    background-color: #bbada0;
    position: relative;
}

#background_box>.kuai{
    /* 250/4=60....10 */
/* 
    > 子代选择
*/
    width: 50px;
    height: 50px;
    margin-top: 10px;
    margin-left: 10px;
    background-color: #cdc1b4;
    float: left;
}
#background_box>.box{
    top:10px;
    left: 10px;
    
    width: 50px;
    height: 50px;
    position: absolute;
    
    background-color: red;

    transition-property: left,top,transform;
    /* 你要过渡的属性 */
    transition-duration: 0.1s;
    /* 过渡动画的时间 */
    transition-timing-function: linear;
    /* 过渡的速率变化 */


    transform: scale(1);
    /* transform: scale(1); 正常大小 */
    
    line-height: 50px;
    text-align: center;
    font-size: 20px;
    font-weight: 800;
    color: white;
}
#background_box>.game_over_box{
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(238,228,218,.5);
    /* display: flex; */
    display: none;
    /* 正常的元素布局从左到右排列 */
    flex-direction: column;
    /* 把正常的变成从上到下布局 */
    justify-content: center;
    /* 水平布局 */
    align-items: center;
    /* 垂直布局 */
    z-index: 5;
}
#background_box>.game_over_box>.title{
    font-size: 24px;
    font-weight: 800;
    margin-bottom: 40px;
}
#background_box>.game_over_box>.button{
    font-size: 16px;
    user-select: none;
    background-color: sienna;
    border-radius: 3px;
    padding: 2px 14px;
    color: white;
    cursor: pointer;
}
